The sublingual BA isn't that low where IV is 8x stronger. Most sources have it being a little more than 2x as strong, so my point was more that the IV duration is so much shorter that he would have to dose that much more often to hold him all day at a dose equivalent to 8mg.
The newest formulations have a 55% sublingual BA and the old ones around 35-40 I think so I really don't think it's 8x as potent when IVd. Also I said 1mg max not 2mg, I know that's a huge difference and I wouldn't even do 1mg in a shot but was using it as more of an example of how much more often you would need to dose. It's just so much shorter acting when IVd that some people find that they have to do more than the equivalent compared to sublingually due to how fast it wears off. Simply put, if 8mg sublingually holds him all day that doesn't mean the equivalent IVd would, although at doses that high it should.
Having said all of that I would never do more than 3 0.5mg shots in a day if that's the route you are going. It seems that people that microcode do it even more often so I think it's better to do a bit more per dose but less often so you aren't poking at yourself that much. I've never felt anything from taking more than 6mg sublingually in a day so even if it's 4x stronger when IVd then that should be like 1.5mg IVd which would make sense with 3 0.5mg shots in a day. So like I was saying b4, IV has no added benefit for maintenance and you end up dosing at least twice as often for no real reason.
Those sources are wrong. They are based off of the bioavailability of a liquid formulation( or the new Zubsolv) being close to 50%.
The problem is that the half-life is EXPONENTIALLY shorter. So even if the BA we're 100%, IV would still be exponentially more potent.
As I stated in my first post, peak plasma from IV buprenorphine is 10-20x higher than sublingual(mean 15).
And the half-life of IV averages 3-4h, vs 24-30. It's not like when you take it sublingually the T1/2 magically increases, it increases because the drug is released from mucous membranes so slowly. They also believe that they're is a shallow depot effect from sublingual buprenorphine.
It is the same thing with rectal administration. With many drugs, using either the sublingual or rectal route results in a longer half-life. In exchange, plasma levels are lower.
Think of it as sublingual having a similar effect to taking extended release medication; the amount released is the same, but it is released (much) more slowly, resulting in an extended duration. Plasma levels are correspondingly lower.
In buprenorphine's case, sublingual BA is only 40-60%, and that is with a liquid formulation! With Suboxone/Subutex, bioavailability varies anywhere from 13-35%.
So really they're is no comparison between IV and sublingual. For me, 1mg IV gives a greater effect than a full tablet(without dissolving in water). That will vary, but it is invariably several times more potent.
